The present invention relates to a wrapping method and a wrapping machine for wrapping an elongated article with a cover material decorated with a desired pattern.
A wrapping machine for wrapping an elongated article such as a pressed compilation of wood chips and an extruded product of plastic or metal substances with a wrapping sheet is known as disclosed in Japanese Examined Utility Model Patent Publication Kokoku No. 46925/1994. The machine generally has a conveyor for conveying the elongated article and a roll holder for holding a roll of the wrapping sheet decorated with a desired pattern such as the grain of wood or stone and the like. During the conveyance of the article, the wrapping sheet is drawn out from the roll and an adhesive is applied on one side thereof. Then, the sheet is fed to the article surface and pressed by a plurality of pressing rollers beside the conveyer, whereby the article is wrapped with the sheet adhering thereto.
When the wrapping sheet is manufactured from a synthetic resin, a thick sheet can be obtained, more than 100 microns thick, for instance. Therefore, by wrapping the article with such a thick sheet, cracks, flaws and roughness of the article surface are fully veiled, and thus, an appearance of the article is improved to exhibit a quality taste. But, in case of a fire or incineration, the synthetic resin-made sheet generates noxious fumes to cause environmental pollution. In addition, since the separation of the sheet and the article is difficult, the wrapped article is hard to be recycled.
On the other hand, a transfer printing technique can be used as well for wrapping the elongated article with a cover material. The technique employs a transfer printing film in place of the wrapping sheet. The printing film comprises a substrate film generally formed of a synthetic resin and a transfer layer having a desired pattern on the substrate film. Alternatively, the printing film may have a release layer between the substrate film and the transfer layer. The printing film is affixed to the article, and then, the transfer layer is transferred to the article from the substrate film by heat and press. Finally, the resin-made substrate film is peeled off from the article. Therefore, this technique can avoid the above-mentioned drawbacks.
However, since the article is wrapped with a thin transfer layer, the cracks, flaws and roughness of the article appear through the thin layer, and thus, the quality article superior in appearance cannot be obtained. In order to solve this problem, the article should be dressed to have a smooth surface before wrapping. But, this needs an additional dressing step.
Consequently, it is an object of the present invention to manufacture a wrapped elongated article having a smooth, excellent, quality surface superior in appearance by using a transfer printing film in a simplified manner.
According to the wrapping method of the present invention, it comprises a step for applying a hot melt type adhesive on a transfer layer of a transfer printing film, a step for affixing the printing film to an elongated article by means of the hot melt type adhesive, a step for transferring the transfer layer to the article from a substrate film of the transfer printing film, and a step for peeling off the substrate film.
According to the wrapping machine of the present invention, it comprises holding means for holding a roll of a transfer printing film, applying means for applying a hot melt type adhesive on a transfer layer of the printing film drawn out from the roll, conveying means for conveying an elongated article, affixing means for affixing the printing film by means of the adhesive to the article being conveyed by the conveying means, and transferring means for transferring the transfer layer to the article.
A transfer printing film comprising a substrate film and a pattern-decorated transfer layer on the substrate film is drawn out from a roll thereof, and fed to a surface of the article which is conveyed horizontally by the convey rollers, for instance. The printing film is subject to an adhesive application during the travel to the article on the rollers. A hot melt type adhesive is employed as the adhesive, which type of adhesive can be easily regulated in thickness by an applicator. The printing film adheres to the article by the thick hot melt type adhesive to the article surface, and pressed with heat to transfer the decorated transfer layer with adhesive together integrally. Peeling off the substrate film finally, a smooth, quality and decrated article with a pattern such as the grain of wood or stone is obtained superior in appearance, because the thick hot melt type adhesion between the transfer layer and the article satisfactorily cover the cracks, flaws, roughness of the article.
Although the obtained elongated article is wrapped with the thin transfer layer, the hot melt type adhesive can cover the cracks, flaws, roughness of the article. Besides, the hot melt type adhesive can be regulated to a desired thickness. Therefore, a smooth, quality and decrative article can be obtained superior in appearance.
Furthermore, the substrate film is finally removed from the article, and thus, although the substrate film is formed of a synthetic resin, the wrapped article obtained by the method or machine of the invention never generates noxious fumes to cause environmental pollution in case of a fire or incineration. In addition, the article obtained by the method of the invention is easy to be recycled.
The transferring means preferably comprises a press roller for pressing the transfer layer to the article and a heater for heating the press roller.
In this case, the transfer layer having the pattern is thermally transferred, the layer and the hot melt type adhesive are well sticked to the article together integrally and hard to be removed.
Alternatively, the machine of the invention comprises emboss-transferring means for transferring the transfer layer to the article with embossing the layer in place of the transferring means.
In this case, a desired pattern such as the grain of wood or stone and the like in the transfer layer can be realistic by the emboss technique. Furthermore, by regulating the thickness of the hot melt type adhesive beneath the transfer layer, the pattern turns to be more preferably realistic.
The emboss-transferring means preferably comprises an emboss-press roller for pressing the transfer layer to the article with embossing the transfer layer and a heater for heating the emboss-press roller.
In this case, the transfer layer having the pattern is thermally transferred, the layer and the hot melt type adhesive are well sticked to the article together integrally and hard to be removed. Furthermore, since the transfer layer and the hot melt type adhesive are softened by heat, a huge emboss-pressing force is not necessary.